Has there been a year more richly blessed with fine first novels by American writers than this one? Harriet Doerr, Josephine Humphreys, William McPherson, Padgett Powell, Louise Erdrich, Diana O'Hehir all published exceptional first novels during 1984, and now their ranks are joined by yet another: Sheila Bosworth, whose "Almost Innocent" is a sly, sensitive story of a family too closely knit for its own good, a family that eventually disintegrates under the weight of too much love too thoughtlessly indulged.

Readers fortunate enough to have encountered Robb Forman Dew's new novel, "The Time of Her Life," will be struck by certain similarities, entirely accidental and coincidental, between the two books. Both are about eccentric married couples who tend to treat their responsibilities casually, and each couple has a young daughter who is traumatically affected by the deteriorating relationship between her parents and by her own steadily widening understanding of the adult world's chilly realities. The consequences for both families and daughters are quite different, but both novelists consider their characters' predicaments with great subtlety and honesty.

This family is named Calvert. The father, Rand, is artistically gifted, politically liberal and arrested in late adolescence; the mother, Constance, is beautiful, frail, childlike, independent and willful; the daughter, Clay-Lee, is lively and smart, and haunted by all the usual demons who visit a bright, imaginative child. They live in New Orleans, but not in a desirable section; they share a house with another couple on Camp Street, where blue-collar workers and young blue bloods rub shoulders in mutual impecuniousness.

It's a family of just three, but it extends to embrace a considerable network of cousins, uncles, friends and servants, all of whom deeply love these young parents whose match seems to have been made in heaven; as one relative says to another, speaking of Clay-Lee, "They're a love match, Rand and Constance, and loving each other as they do is the best gift they can give this little one." For a long time that seems to be true; the Calverts, though poor by the standards of the aristocracy from which they have sprung, exist blissfully in the chamber of their love, oblivious or indifferent to the realities of the life that swarms around them.

But eventually the world crashes in, in the person of a relative known, for reasons too complicated (though amusing) to elaborate, as Uncle Baby Brother. He bursts in, full of energy and guile and lust; "he had a penchant for straight bourbon, forthright remarks, and making love to married ladies, so long as they weren't married to him." With Constance's help he cajoles Rand into taking a job running a sugar mill, a job that takes Rand away from his artist's studio and, in more ways than one, away from his family. And while Rand works away, Uncle Baby Brother bulls in, trying to capitalize on Constance's frustration at living in conditions far less opulent than those to which as a girl she had been accustomed.

There's a lot of adult maneuvering going on here, both subtle and crude, and witness to all of it is Clay-Lee, who ruefully wonders "when my own life was going to begin and I could stop being an audience at other people's." For her, as for young Jane in Dew's novel, it is too much:

"I was a child! It was true that I eavesdropped a lot, but, still, why did grown-ups expect me to listen to things that made me afraid? People went out of their way to protect other children from the truth. Jimmy Leche, a second-grader who lived down the road, had a mother who'd never even told Jimmy that his father had fallen into a paper mill last Holy Thursday. Jimmy still thought his daddy was on a holiday at Six Flags Over Texas, out in Dallas-Fort Worth. Born old, Sis Honorine said I was. I was sick of feeling old as a grandmother and powerless as an infant at the same time."

It's a terrible position for a child to be in, and what Clay-Lee eventually witnesses is terrible as well. Yet though the note on which the novel ends is sad, "Almost Innocent" is anything but morose or dispiriting. To the contrary, all of Sheila Bosworth's characters are so filled with spunk and grit that the novel crackles with energy. Its only weak section is the second of its three parts, in which the narrative is briefly and somewhat awkwardly transferred from Clay-Lee to an older friend of her mother's. But the abrupt change of viewpoint that this creates quickly fades away, and for the rest of the way the reader is in the hands of a skilled, resourceful writer who knows what she is doing and does it with admirable craftsmanship.